Nord-lock washers have cams on one side with a greater rise than the pitch of the bolt. In addition, they have radial teeth on the opposite side. The washers are installed in pairs, cam face to cam face.

When the bolt and/or nut is tightened, the teeth grip and seat the mating surfaces. The teeth lock the washers in place, allowing movement only across the face of the cams. The tension created makes the bolt/nut self-locking.